package com.centit.util;

/**
 * @Auther: 皇甫壮
 * @Date: 2018-6-29 09:47
 * @Description:
 */
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.lang3.StringUtils;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.Claim;
import com.auth0.jwt.interfaces.DecodedJWT;

/**
 * APP登录Token的生成和解析
 *
 */
public class JwtToken {
    /** token秘钥，请勿泄露，请勿随便修改 backups:JKKLJOoasdlfj */
    public static final String appPublicKey="centithpz1234";
    /** token 过期时间: 1天 */
    public static final int calendarField = Calendar.DATE;
    public static final int calendarInterval = 1;
    /**
     * JWT生成Token.<br/>
     *
     * JWT构成: header, payload, signature
     *
     * @param usercode
     *         登录成功后用户user_id, 参数user_id不可传空
     */
    public static String createToken(String usercode,String loginName) throws Exception {
        Date iatDate = new Date();
        // expire time
        Calendar nowTime = Calendar.getInstance();
        nowTime.add(calendarField, calendarInterval);
        Date expiresDate = nowTime.getTime();
        // header Map
        Map<String, Object> map = new HashMap<>();
        map.put("alg", "HS256");
        map.put("typ", "JWT");
        // build token
        // param backups {iss:Service, aud:APP}
        String token = JWT.create().withHeader(map) // header
                .withClaim("iss", "Service") // payload
                .withClaim("aud", "APP").withClaim("usercode", null == usercode ? null : usercode.toString())
                .withClaim("loginName",loginName)
                .withIssuedAt(iatDate) // sign time
                .withExpiresAt(expiresDate) // expire time
                .sign(Algorithm.HMAC256(appPublicKey)); // signature
        return token;
    }
    /**
     * 解密Token
     *
     * @param token
     * @return
     * @throws Exception
     */
    public static Map<String, Claim> verifyToken(String token) {
        DecodedJWT jwt = null;
        try {
            JWTVerifier verifier = JWT.require(Algorithm.HMAC256(appPublicKey)).build();
            jwt = verifier.verify(token);
        } catch (Exception e) {
            // e.printStackTrace();
            // token 校验失败, 抛出Token验证非法异常
        }
        return jwt.getClaims();
    }
    /**
     * 根据Token获取user_id
     *
     * @param token
     * @return user_id
     */
    public static String getAppUID(String token) {
        Map<String, Claim> claims = verifyToken(token);
        Claim usercode_claim = claims.get("usercode");
        if (null == usercode_claim || StringUtils.isEmpty(usercode_claim.asString())) {
            // token 校验失败, 抛出Token验证非法异常
            return "";
        }
        return usercode_claim.asString();
    }
}
